Aging resistance shape selective catalyst with enhanced activity

ABSTRACT

A shape selective catalyst useful in a variety of hydrocarbon conversion processes such as cracking, hydrocracking, hydrofining, isomerization, dewaxing, and the like, is obtained from the process which comprises steaming a precursor crystalline aluminosilicate in the hydrogen or ammonium form having a silica-alumina ratio greater than 12, a constraint index between about 1 and about 12 and an alpha value greater than about 20 in the presence of ammonia to provide a crystalline aluminosilicate having an alpha value of from about 10 to about 150 and thereafter ion-exchanging the steamed precursor with an alkali metal cation under conditions effective to further reduce the alpha value of the crystalline aluminosilicate to less than about 10.

This is a division of copending application Ser. No. 331,117, filed Dec.16, 1981, now U.S. Pat. No. 4,402,866.

BACKGROUND OF THE INVENTION

This invention concerns a modified high silica-to-alumina ratio acidiccrystalline zeolite catalyst of a special group such a ZSM-5 havingincreased activity and decreased aging rate when employed in a varietyof hydrocarbon conversion processes.

It is well known in the petroleum refining art to improve the quality ofvarious hydrocarbon oils by treating them with catalysts under varyingconversion conditions to effect such reactions as cracking,hydrocracking, hydrofining, isomerization, dewaxing, and the like. Inthese processes, operating catalyst life usually depends on the natureof feedstock, the severity of the operation and often, on the nature andthe extent of operational upsets. Gradual catalyst deactivation iscountered by incrementally raising the operating temperature to maintainthe required conversion.

Numerous investigators have demonstrated that the activity ofsilica-alumina and clays used in various acid-type catalytic reactionsdepends in part on the degree of hydration of the surface. The effect ofwater on hydrocracking was reported by T. Y. Yan (see Journal ofCatalysis 25, 204-211 (1972)). Yan evaluated the addition of water,introduced as 2-pentanol or water vapor, on the hydrocracking activitiesof palladium impregnated rare earth exchanged zeolite X and a platinumimpregnated zeolite HY. The addition of 3 wt % 2-pentanol to the feed orsaturating the feed with water vapor at 75% reduced the temperaturerequired for a 60% conversion of n-hexadecane by 12° F. Yan furthershowed that the activation was due to water and not by the penteneproduced by the dehydration of 2-pentanol. The promotional effect ofwater on the hydroprocessing of a commercial feedstock was found to beminimal. Furthermore, water failed to promote zeolite HY. Minachev, etal. have reported in Soviet Scientific Reviews, Section B., ChemistryReviews, Vol. 2, 1-6 (1980) that sodium forms of zeolites are notpromoted by water. In addition, Ward (Journal of Catalysis, 11,238-250(1968) studied the influence of small amounts of water on the acidity ofseveral alkali, alkaline earth, hydrogen and mixed cation zeolites byobserving changes in the infrared spectrum of chemisorbed pyridine.Water had no marked effect on the acidity of alkali cation X and Yzeolites.

Water and water precursors have also been disclosed in the patent art asuseful in enhancing catalytically promoted petroleum processes. Waterhas been disclosed as enhancing the activity of metal catalystssupported on inorganic metal oxide supports in such processes asreforming (U.S. Pat. Nos. 2,642,383 to Berger, et al. and 3,649,524 toDerr, et al.), hydrodesulfurization (U.S. Pat. No. 3,720,602 to Riley,et al.); dehydrogenation (U.S. Pat. No. 3,907,921 to Winter) andhydrocracking (U.S. Pat. No. 4,097,364 to Egan). In addition, water hasbeen found useful in petroleum processing in promoting the activity ofcrystalline aluminosilicates, such as zeolite X and Y (U.S. Pat. Nos.3,943,490 to Plank, et al. (cracking); 3,546,100 to Yan (hydrocracking)and 4,097,364 to Egan (hydrocracking) and ZSM-5 (U.S. Pat. No. 4,149,960to Garwood, et al. (dewaxing). Garwood, et al. disclose that dewaxing ofgas oils wth a ZSM-5 type zeolite in hydrogen form is enhanced bycofeeding water with the gas oil feed. The benefits obtained areimprovements in coke laydown and catalyst aging rates. There is nosuggestion that a sodium exchanged ZSM-5 type zeolite has catalyticdewaxing capability or that the presence of water would benefit such azeolite.

In some particular petroleum conversion processes involving cracking acertain class of compounds in a feedstock may be converted to modify acharacteristic of the whole feedstock. Exemplary of the latter type ofconversion is catalytic hydrodewaxing whose principal purpose is toreduce the pour point of wax containing mineral oils. Pour point is thetemperature at which an oil will not flow, as determined by standardizedtest procedures. The waxy compounds are long carbon chain moleculeswhich tend to crystallize on cooling of the oil to an extent such thatit will not flow, hence it may not be pumped or transported by thepipelines at ambient temperatures.

Catalytic dewaxing as practiced today involves the shape selectiveconversion of straight and slightly branched aliphatic compounds of 12or more carbon atoms, viz, the waxy molecule, to reduce the pour point,pumpability and/or viscosity of mineral oil fractions which containthese waxy constituents.

Particularly effective catalysts for catalytic dewaxing include zeoliteZSM-5 and related porous crystalline aluminosilicates as described inU.S. Pat. No. Re. 28,398 of Chen, et al. As described in that patent,drastic reductions in pour point are achieved by catalytic shapeselective conversion of the wax content of heavy stocks with hydrogen inthe presence of a dual-functional catalyst of a metal plus the hydrogenform of ZSM-5. The conversion of waxes is by scission of carbon tocarbon bonds (cracking) and production of products of lower boilingpoint than the waxes. However, only minor conversion occurs in dewaxing.For example, Chen et al. describe hydrodewaxing of a full range shaleoil having a pour point of +80° F. to yield a pumpable product of pourpoint at -15° F. The shift of materials from the fraction heavier thanlight fuel oil to lighter components was in the neighborhood of 9%conversion.

Among the less specialized techniques for producing products of lowermolecular weight than the hydrocarbon charge stock are catalyticcracking and catalytic hydrocracking. Catalytic cracking involvescontacting the heavy hydrocarbon charge with a porous acidic solidcatalyst at elevated temperatures in the range of 850° to 1000° F. toyield the desired lower boiling liquid product of greater value than theliquid charge (e.g. motor gasoline) together with normally gaseoushydrocarbons and coke as byproducts. Hydrocracking employs a porousacidic catalyst similar to that used in the catalytic cracking butassociated with a hydrogenation component such as metals of Groups VIand VIII of the Periodic Table. An excess of hydrogen is supplied to thehydrocracking reactor under superatmospheric pressure at lowertemperatures than those characteristic of catalystic cracking, say about650° F.

Since the introduction of zeolite catalysts as exemplified by U.S. Pat.No. 3,140,249, a large proportion of the capacity for catalytic crackingand hydrocracking has been converted to use of such highly activecatalysts. The high activity zeolite catalysts are characterized by verylow content of alkali metal. Sodium, for example, is present as a cationin synthetic faujasites by reason of their manufacture. Expensive ionexchange operations are carried out in the preparation of cracking andhydrocracking catalysts from synthetic faujasite to replace the sodiumor other alkali metal by protons or poly-valent metal cations,especially rare earth metal cations.

It has been recognized that such zeolites can function as catalysts whencontaining a moderate percentage of sodium. Thus, U.S. Pat. No. Re.26,188 to Kimberlin, et al. exhibits data showing cracking activity of afaujasite from which only one-third of the sodium has been removed byion exchange. The extremely high activity of such catalysts as zeoliteZSM-5 has been moderated for specialized purposes by using the zeolitein the partially sodium form. See, for example, U.S. Pat. No. 3,899,544.

Zeolite ZSM-5 preparation is described in U.S. Pat. No. 3,702,886 whichalso describes several processes in which the zeolite is an effectivecatalyst, including cracking and hydrocracking. That zeolite is shown tobe prepared from a forming solution which contains organic cations,namely alkyl substituted ammonium cations. Those large organic cationsthen occupy cationic sites of the zeolite and block pores at leastpartially. The conventional method for removing the organic cations isto burn them out with air at elevated temperature, leaving a proton atthe site previously occupied by the organic cation. Sodium, or otheralkali metal, at other cationic sites may then be ion exchanged toprovide protons or multivalent metals as desired to prepare catalystsfor cracking, hydrocracking and other purposes.

The acid activity of zeolite catalysts is conveniently defined by thealpha scale described in an article published in Journal of Catalysis,Vol. VI, pp 278-287 (1966). In this test, the zeolite catalyst iscontacted with hexane under conditions prescribed in the publication andthe amount of hexane which is cracked is measured. From this measurementis computed an "alpha" value which characterizes the catalyst for itscracking activity for hexane. The entire article above referred to isincorporated herein by references. The alpha scale so described will beused herein to define activity levels for cracking n-hexane. And, inparticular, for purposes of this invention, a catalyst with an alphavalue of less than about 10 and preferably less than about 1 will beconsidered to have substantially little activity for cracking n-hexane.

The shape selective catalysis of zeolites is defined by the ConstraintIndex scale described in an article published in the Journal ofCatalysis, Vol. 67, pp 218-222 (1981). In this test, the zeolitecatalyst is contacted with a mixture of hexane and 3-methylpentane underconditions set forth in the publication and the amount of hexane and3-methylpentane cracked is measured. From this measurement a constraintindex value is computed which is related to the ability of the zeolitefor shape selective catalysis. The entire article above is incorporatedherein by references. The contraint index scale so described will beused herein to describe the ability of zeolite for shape selectivecatalysis.

U.S. Pat. No. 4,247,388 to Banta, et al. discloses that the catalyticperformance of certain acidic zeolites such as those of the ZSM-5 typein hydrodewaxing operations is improved by controlling the alphaactivity of such zeolites to within the range of 55-150, e.g., bytreatment with steam.

U.S. Pat. No. 4,284,529 to Shihabi discloses improvements in pour pointreduction by means of catalytic dewaxing employing a catalyst preparedfrom a ZSM-5 type zeolite having a constraint index of about 1 to 12.This dewaxing process employs a low acidity form of zeolite such asZSM-5 or ZSM-11 in which the low acidity is imparted by steaming thezeolite to reduce its cracking acitivity to an alpha value of not lessthan about 5, followed by base ion exchange with an alkali metal cationto reduce the alpha value to not greater than 1.0. A preferred catalystis referred to therein as a presteamed Na ZSM-5 and is employed to dewaxcrude oils and other waxy feedstocks in the presence or absence of addedhydrogen. These catalysts are effective at start-of-run temperature ofabout 640° F. and exhibit excellent aging behavior in the presence ofhydrogen. However, in the absence of hydrogen these catalysts exhibit agradual aging requiring a daily increase of about 1°-10° F. in thereaction temperature. Dewaxing processes conducted with presteamedsodium ZSM-5 in the absence of hydrogen exhibit, on the average, cycletimes of several weeks between catalyst regenerations because ofcatalyst aging.

The presteamed base exchanged catalyst disclosed in U.S. Pat. No.4,289,529 is particularly suited to reducing the pour point of waxycrude oils. This catalyst is especially resistant to the metals,nitrogen and sulfur often associated with crude oils and it does notcause the formation of appreciable quantities of C₃ gaseous products sothat the liquid recovery from crude dewaxing is often 98% or better.Ideally, crude oil dewaxing should be practiced at well-head so as topermit easy transporting of the dewaxed crude by pipeline. Where aneconomical source of hydrogen is available, the above described processis commercially feasible. However, practicing this process without asource of hydrogen could be economically attractive if the cycle timesbetween catalyst regenerations are sufficiently long.

SUMMARY OF THE INVENTION

It has now been very surprisingly discovered that the dewaxing processof U.S. Pat. No. 4,284,529 can be significantly improved especially asapplied to a feed having a relatively high content of poisonouscompounds such as nitrogen as in Shengli or Nigerian gas oil, shale gasoil, etc., or a feed relatively high in both nitrogen and oxygencomponents, e.g., coker gas oil or a whole crude, such as Taching crude,by employing as catalyst for said dewaxing, a composition obtained bythe proces which comprises steaming a precursor crystallinealuminosilicate in the hydrogen or ammonium form having a silica-aluminaratio greater than 12, a constraint index between about 1 and about 12and an alpha value greater than about 20 in the presence of ammonia toprovide a crystalline aluminosilicate having an alpha value of fromabout 10 to about 150 and thereafter ion-exchanging the steamedprecursor with an alkali metal cation under conditions effective tofurther reduce the alpha value of the crystalline aluminosilicate toless than about 10.

A catalyst prepared in accordance with this invention possesses enhancedstability characteristics for nitrogen, sulfur and oxygen compounds ascompared with the catalyst of U.S. Pat. No. 4,284,529 and relatedcatalysts and permits cracking processes to be carried out at lowertemperatures with or without added gas such as hydrogen.

In addition to its usefulness in dewaxing, a catalyst prepared in theaforedescribed manner is also useful for catalyzing a variety of otherpetroleum/hydrocarbon conversions such as up-grading Fischer-Tropschproducts, producing xylene from a mixture of ethyl benzene, paraffinsand xylene isomers and up-grading naphtha to higher octane products.Furthermore, in petroleum conversions where hydrocracking, hydrofiningand/or isomerization is desired, the aforedescribed catalyst can beassociated with a hydrogenation component consisting of metals of groupVI and VIII of the Periodic Table.

The catalyst used in the present invention is a low acidity form of aclass of zeolites which have been found to be extremely active in theacid form. In that form the cationic sites are occupied by protonsintroduced by ion exchange with an acid or an ammonium (includingsubstitued ammonium) cation which is then decomposed by heat to aproton. Alternatively at least a portion of the cationic sites may beoccupied by polyvalent metals. For use in the present invention, thesevery high acidities inherent in zeolites, such as zeolite ZSM-5, aredrastically reduced. Preferably, the acidity is reduced by extensive ionexchange with lithium, sodium or other alkali metal. The invention mayalso be practiced with such zeolites of very high silica/alumina ratioor by steaming of the active form of the zeolite. It will be recognizedby those skilled in the art of zeolite catalysis that substitution ofsodium or like cation and steaming are generally recognized as means to"poison" a zeolite catalyst by severely impairing its activity. Theseagencies are generally avoided in preparation and use of zeolitecatalysts in cracking or hydrocracking.

In a particular embodiment of this invention, a zeolite having the abovedescribed characteristics and an alpha value greater than about 20 isconverted to a low acidity catalyst by contact with steam and ammonia ata temperature of about 600° F. to about 2,000° F. and at a pressure offrom about subatmospheric to about 1,000 psig, preferably at atemperature of from about 800° F. to about 1,200° F. and a pressure offrom about atmospheric to about 500 psig for a period of time effectiveto provide an alpha value of from about 10 to about 150 and preferablyfrom about 20 to about 120. The concentration of ammonia can vary fromabout 1 ppm to about 30%, and preferably from about 0.1% to about 20%,by weight of the total steam-ammonia mixture. The zeolite steamed in thepresence of ammonia in accordance with the foregoing procedure is thenbase exchanged with alkali metal cations to an extent effective toreduce its alpha value to less than about 20, preferably less than about5 and most preferably less than about 1. In essence, base exchange isconducted under conditions which substantially eliminate the activity ofthe zeolite for cracking n-hexane although a catalyst with an alphavalue even below 0.1 can have some residual activity for n-hexanecracking. However, this residual activity is so small compared with themore highly acidic forms of the same catalyst as to warrant thecharacterization "substantially eliminated." Alkali metal cations,preferably lithium and sodium, are particularly effective for thispurpose. Catalysts prepared by the particular procedure just describedare highly efficient for dewaxing, and especially for dewaxing crudeoils. In such service, the catalyst is effective as start-of runtemperatures of about 640° F. or even less, and exhibit excellent agingbehavior and, as a consequence, long cycle life.

In general, the catalysts used in accordance with this invention arecrystalline zeolites having a silica/alumina ratio greater than 12 and aConstraint Index (C.I.) between about 1 and about 12. The zeolites aregenerally termed ZSM-5 type zeolites. These zeolites and their use asdewaxing catalysts are described in U.S. Pat. Nos. 4,149,960 and4,284,529. The entire contents of both are incorporated by referenceherein.

The preferred class of zeolites defined herein are ZSM-5 type zeolitesas exemplified by ZSM-5, ZSM-11, ZSM-12, ZSM-35, ZSM-38, with ZSM-5being particularly preferred.

ZSM-5 is more particularly described in U.S. Pat. No. 3,702,886, theentire contents of which are incorporated herein by reference.

ZSM-11 is more particularly described in U.S. Pat. No. 3,709,979, theentire contents of which are incorporated herein by reference.

ZSM-12 is more particularly described in U.S. Pat. No. 3,832,449, theentire contents of which are incorporated herein by reference.

ZSM-35 is more particularly described in U.S. Pat. No. 4,016,245, theentire contents of which are incorporated herein by reference.

ZSM-38 is more particularly described in U.S. Pat. No. 4,046,859, theentire contents of which are incorporated herein by reference.

The zeolites used according to the invention have low alpha values, lessthan about 10. Preferably, the alpha value is less than unity. As noted,the low acid activity may be achieved by using zeolites of very highsilica/alumina ratio or by severe high temperature steaming of zeoliteshaving lover silica/alumina ratio, for example zeolite ZSM-5 of ratio 40may be treated with 90% steam-10% ammonia at 1200° F. and atmosphericpressure for a period of time (several hours) adequate to reduce theacid activity to the necessary level.

Preferably, the low acidity is achieved by extensive ion exchange of thesteam and ammonia treated zeolite with sodium or other alkali metalcation. Silica/alumina ratios in the range of 12 to aluminum free willgenerally characterize the zeolites preferred in this form of theinvention. Particularly preferred zeolites may be in silica/aluminarange of 20-2000. It is found that the sodium forms of the zeolitesusually are less efficient for dewaxing than are the acid forms but givebetter overall results measured as conversion, particularly since theconversion products are low in gaseous hydrocarbons. In the embodimentof this invention wherein steaming is combined with base exchange, i.e.,by steaming to reduce the alpha value by at least 10 units but not belowan alpha value of about 10 followed by base exchange with an alkalimetal under conditions effective to substantially reduce hexane crackingactivity, the zeolite catalyst has high activity for dewaxing asmeasured by its effectiveness at temperatures in the range of about 650°F. to about 800° F.

Sodium content of the zeolites will vary inversely with thesilica/alumina ratio since it is the aluminum atoms which providecationic sites suitable for acceptance of the alkali metal ion.

In preferred forms of the invention, the zeolite contains nohydrogenation metal component. Therefore, dewaxing processes can becarried out in the presence or absence of added gas. Thus the preferredcatalyst is a presteamed, ammonia-treated sodium exchanged ZSM-5zeolite. These low acidity alkali metal zeolites are prepared by ionexchange of the zeolite with an aqueous solution of an alkali metal saltor hydroxide at moderate pH values. In the following examples, care wastaken to assure nearly complete ion exchange. Thus the observed activityappears truly representative of low acidity zeolites.

Although the process of the invention may be practiced in the absence ofadded gas, it is preferred that gas be added to the process. Such gasesas hydrogen, C₁ -C₃ hydrocarbons or mixtures thereof may be employed.Therefore, gaseous hydrocarbons, such as methane, associated with crudeoil may be employed.

In on-site whole crude upgrading the process may be conducted in thepresence of methane which may be supplied per se or provided as part ofthe gaseous hydrocarbons existing in the downhole formation with thecrude oil and which are produced together with the crude oil at the wellhead. When operated in this fashion, i.e., under methane pressure, it ispreferred to operate by the trickle technique with methane flowingconcurrently downward with mixed vapor and liquid phase hydrocarbons.

Temperature of the reaction is between 600° F. and 850° F. depending onthe feed. However, with the particular catalyst utilized herein which isprepared by steaming to an alpha value of not less than about 10followed by base exchange with alkali to an alpha value of less thanabout 10, satisfactory activity has been found at temperatures less than700° F. Many charge stocks will undergo some thermal cracking attemperatures above about 800° F. with resultant production of undesiredgaseous hydrocarbons thereby losing one advantage of the invention tothe extent that thermal cracking takes place.

Pressures employed will vary according to the technique being used. Forliquid full reactor operation, the minimum pressure will be thatnecessary to maintain the charge in liquid phase at the temperature ofreaction. In any event, the pressure will be above about 200 psi. Thereappears to be no maximum pressure limit imposed by effectiveness of thecatalyst, but costs for capital installation and operation ofcompressors and the like rise rapidly for pressures in excess of 2,000psi. When methane or hydrogen or any gas is added to the system, it ispreferred to operate below that level for economic reasons. Gascirculation may be maintained at from 0 to 15,000 scf/bbl.

Space velocity will vary somewhat with the type of feed, permitting ahigher space velocity for a feedstock which is easily dewaxed.

In general, space velocity will range from about 0.1 liquid volume ofhydrocarbon charge per volume of catalyst per hour (LHSV) up to about5.0 LHSV. For most charge stocks, preferable LHSV will range from about0.3 to about 1.0

In the examples which follow, Examples 1 to 3 illustrate the dewaxing ofNigerian gas oil (boiling range 540°-870° F.), a feed relatively high incatalyst-inactivating nitrogen.

EXAMPLES 1 TO 3

The hydrogen form of ZSM-5 was contacted with 100% steam at 800° F. for23 hours to an alpha value of 72 followed by sodium exchange to an alphaof less than 0.5. Nigerian gas oil was processed over this catalyst. Thegas oil feed had the following properties:

Hydrogen, wt.% 13.01

Sulfur, wt.% 0.24

Nitrogen, ppm 660

Pour Print, °1--75

                  TABLE I                                                         ______________________________________                                                        Example                                                                       1       2      3                                              ______________________________________                                        Reaction Temp., °F.                                                                      760       770    780                                        LHSV              1.1       1.3    1.3                                        Time on Stream, Days                                                                            10        16     17                                         System Pressure, psig                                                                           570       570    570                                        H.sub.2 - Circulation, SCF/BBL                                                                  1,200     1,100  1,100                                      Yields, wt. %                                                                 C.sub.1 -C.sub.3  2         2      3                                          C.sub.4 -330° F.                                                                         16        15     20                                         330° F. +  82        82     77                                         330° F. + Pour Point, °F.                                                         40        35     5                                          ______________________________________                                    

EXAMPLES 4 AND 5

Substantially the same catalyst steaming procedure as that described inExamples 1 to 3 was employed except that the ammonium form of ZSM-5 wasemployed generating ammonia in situ during steaming. The steamed,ammonia-treated ZSM-5 had an alpha value of 71 after 23 hours ofsteaming and following sodium-exchange, had an alpha value of less than0.5. The Nigerian gas oil of Examples 1 to 3 was processed over thiscatalyst under the conditions and with the results set forth in Table IIas follows:

                  TABLE II                                                        ______________________________________                                                            Example                                                                       4    5                                                    ______________________________________                                        Reaction Temp., °F.                                                                          770    760                                              LHSV                  1.52   1                                                Time on Stream, Days  21     26                                               System Pressure, psig 550    530                                              H.sub.2 - Circulation, SCF/BBL                                                                      1,650  2,200                                            Yields, wt. %                                                                 C.sub.1 -C.sub.3      3      3                                                C.sub.4 -330° F.                                                                             20     20                                               330° F. +      77     77                                               330° F. Pour Point, °F.                                                               10     -10                                              ______________________________________                                    

The data in Table II clearly demonstrate the superior performance of thelow acidity catalyst that was prepared in accordance with the process ofthis invention.

What is claimed is:
 1. In a process for the catalytic dewaxing of ahydrocarbon fraction under catalytic dewaxing conditions wherein theimprovement comprises employing as catalyst for said dewaxing acomposition obtained from the process which comprises steaming aprecursor crystalline aluminosilicate in the hydrogen or ammonium formhaving a silica-alumina ratio greater than 12, a constraint indexbetween about 1 and about 12 and an alpha value greater than about 20 inthe presence of ammonia to provide a crystalline aluminosilicate havingan alpha value of from about 10 to about 150 and thereafterion-exchanging the steamed precursor with an alkali metal cation underconditions effective to further reduce the alpha value of thecrystalline aluminosilicate to less than about
 10. 2. In a process forthe catalytic hydrocracking of a hydrocarbon oil under catalytichydrocracking conditions wherein the improvement comprises employing ascatalyst for said hydrocracking a composition obtained from the processwhich comprises steaming a precursor crystalline aluminosilicate in thehydrogen or ammonium form having a silica-alumina ratio greater than 12,a constraint index between about 1 and about 12 and an alpha valuegreater than about 20 in the presence of ammonia to provide acrystalline aluminosilicate having an alpha value of from about 10 toabout 150 and thereafter ion-exchanging the steamed precursor with analkali metal cation under conditions effective to further reduce thealpha value of the crystalline aluminosilicate to less than about 10,said composition being present in association with a hydrogenationcomponent.
 3. The process claimed in claim 2, wherein said hydrogenationcomponent consists of metals of group VI and VIII of the Periodic Table.